To answer the question early in the thread as to why VPLive helps folks over 3000 feet...
The Vantage Pro provides only Sea Level Pressure (SLP). This is a derived value that is the result of a calculation that takes the raw sensor pressure, temperature, humidity and elevation. CWOP does not want SLP, it wants Altimeter, which is a different derived value that is calculated using only raw sensor pressure and elevation. Above around 1000 feet SLP and Altimeter don't track well over the full range of temperatures a station might see. So if you're sending SLP to CWOP, and calibrate your barometer to look right, you will see your QC get increasing off as the average temperature changes, such as when a cold front moves through, or from the general changes of the seasons.
When I first wrote VPLive, it was the only program that properly calcuated and sent altimeter to CWOP. Since then, many of the other weather programs added this feature (some of them using the same code that's in VPLive, since I made it freely available to encourage its use so data quality to CWOP would improve). Virtual Weather Station is one of the few programs that still insist on only sending SLP to CWOP for Vantage Pro stations.
Regarding the inconvenient use of WLK files by VPLive at startup, I am currently in the process of making a new version of VPLive that will download archive data directly from the console, and so will not need to run weatherlink at all.